Inconsistent dates on questions

I am just wondering why sometimes questions are listed under content in a group with a recent date, but when you click on them, they turn out to be much older, with no recent comments. Is it because they have been recently migrated from the old forum?

If someone did a search looking for the answer to their question, and found something from an older thread that was useful to them, and marked it helpful then that tends to bring older threads to the top of the list, but I'm not sure I have ever noticed the date being wrong on them.